I think it's fair to say that Terastal as it is now is completely broken, for multiple reasons that were probably stated more than enough at this point, something obviously needs to be done about it.
I'm just going to say that, at least considering a restriction before an outright ban is the better thing to do, I don't think we are in a rush, and it's easily changeable later, so I'll give my opinion on all initially proposed restrictions.
1 - Showing Tera Type at Preview: It may seem like a good thing since it removes the sheer unpredictability, but I think this is still bad for the meta down the line, since it does not remove Terastal's biggest problem: the fact that every mon has access to two potentially widely different defensive type charts. This is very insanely toxic, it also leads to getting good positioning being not just difficult, but sometimes impossible. It would also not remove the fact that some offensive mons are stupidly strong at abusing Terastal, no matter how predictable it is, take Roaring Moon for example, we just know that shit is gonna Dragon Dance in front of you and Tera into a Flying Type with Acrobatics, but yet you can still easily lose, because positioning is too difficult if 6 mons can change their defensive type chart, and can also turn your good positioning into a reverse sweep.
It would eventually still lead to a chaotic metagame, where the better player may not necessarily win.
2 - Limiting the amount of Mons that can Tera: In my opinion, this is the closest we can get to a "balanced Terastal" without making it stupidly complicated for no reason. It still would have a somewhat "random factor", but it's definetly way less oppressive, good positioning can still be overturned, but is less of a threat over the course of a game, a defensive mon can still choose a better typing to change into to wall a bigger part of the meta, but you also don't have to worry about every single one of them turning your great match-up into a game that you can't win anymore because it removed your win condition.
As to how it should be implemented, the questions you should ask are:
- Do you choose the mon you want to Tera at Preview, or do you choose that in the Builder ?
- If you do choose them in the Builder, how should this be implemented ? Just by having a button or by having a Clause that makes it so only the first mon of a team can Tera ?
- How many of them should be able to Tera ? One, maybe two ?
3 - Limiting to Same-Type Tera: This is honestly silly, as it only really nerfs defensive mons who generally don't want to use Same-Type Tera, but something to cover bad match-ups, bringing the offensive ones basically less answers, things like Specs Iron Valiant already use Same-Type Tera to sometimes an insane degree, spamming an Adaptability Moonblast that almost has no true switch-in. This would ruin a balance between offense and defense.
4 - Banning Tera Blast: The answer to that is simple, no. Tera Blast is not a move that a lot of mons run in the first place because you don't even know if you are going to Tera that mon in particular, you're generally gonna prefer overall better coverage, banning Tera Blast would basically have no real influence on the meta, to the point where its probably better to not do anything.
So out of the 4, I see Restriction #2 as the better solution, but it also needs clarifications as to how it should work.
Realistically, even that could be prove to be too much for the metagame to handle, which in when we could outright ban the mechanic.
There's also the proposition of "Useless Item Tera".
And while I really like this just meta-wise, it's really not intuitive for a first time player which might get lost and might quit as a result, which I don't think is a wanted effect of just trying to fix a broken mechanic, we probably should keep it as simple and straight to the point as possible.
So, TL;DR: I think we should look into restricting Terastal first, and then if it proves to be too much, we ban it. I think limiting the amount of mons that can Tera in a team is the best way we can balance this broken mess while keeping it simple.
I'm just going to say that, at least considering a restriction before an outright ban is the better thing to do, I don't think we are in a rush, and it's easily changeable later, so I'll give my opinion on all initially proposed restrictions.
1 - Showing Tera Type at Preview: It may seem like a good thing since it removes the sheer unpredictability, but I think this is still bad for the meta down the line, since it does not remove Terastal's biggest problem: the fact that every mon has access to two potentially widely different defensive type charts. This is very insanely toxic, it also leads to getting good positioning being not just difficult, but sometimes impossible. It would also not remove the fact that some offensive mons are stupidly strong at abusing Terastal, no matter how predictable it is, take Roaring Moon for example, we just know that shit is gonna Dragon Dance in front of you and Tera into a Flying Type with Acrobatics, but yet you can still easily lose, because positioning is too difficult if 6 mons can change their defensive type chart, and can also turn your good positioning into a reverse sweep.
It would eventually still lead to a chaotic metagame, where the better player may not necessarily win.
2 - Limiting the amount of Mons that can Tera: In my opinion, this is the closest we can get to a "balanced Terastal" without making it stupidly complicated for no reason. It still would have a somewhat "random factor", but it's definetly way less oppressive, good positioning can still be overturned, but is less of a threat over the course of a game, a defensive mon can still choose a better typing to change into to wall a bigger part of the meta, but you also don't have to worry about every single one of them turning your great match-up into a game that you can't win anymore because it removed your win condition.
As to how it should be implemented, the questions you should ask are:
- Do you choose the mon you want to Tera at Preview, or do you choose that in the Builder ?
- If you do choose them in the Builder, how should this be implemented ? Just by having a button or by having a Clause that makes it so only the first mon of a team can Tera ?
- How many of them should be able to Tera ? One, maybe two ?
3 - Limiting to Same-Type Tera: This is honestly silly, as it only really nerfs defensive mons who generally don't want to use Same-Type Tera, but something to cover bad match-ups, bringing the offensive ones basically less answers, things like Specs Iron Valiant already use Same-Type Tera to sometimes an insane degree, spamming an Adaptability Moonblast that almost has no true switch-in. This would ruin a balance between offense and defense.
4 - Banning Tera Blast: The answer to that is simple, no. Tera Blast is not a move that a lot of mons run in the first place because you don't even know if you are going to Tera that mon in particular, you're generally gonna prefer overall better coverage, banning Tera Blast would basically have no real influence on the meta, to the point where its probably better to not do anything.
So out of the 4, I see Restriction #2 as the better solution, but it also needs clarifications as to how it should work.
Realistically, even that could be prove to be too much for the metagame to handle, which in when we could outright ban the mechanic.
There's also the proposition of "Useless Item Tera".
2) Useless Item Tera: You must be holding a specific (useless) item, eg Tart Apple, to Tera.
And while I really like this just meta-wise, it's really not intuitive for a first time player which might get lost and might quit as a result, which I don't think is a wanted effect of just trying to fix a broken mechanic, we probably should keep it as simple and straight to the point as possible.
So, TL;DR: I think we should look into restricting Terastal first, and then if it proves to be too much, we ban it. I think limiting the amount of mons that can Tera in a team is the best way we can balance this broken mess while keeping it simple.